ABSTRACT

Waste treatment is an important part of the future global energy portfolio. Challenges associated with implementing energy recovery technology at waste treatment sites include interwoven technical, economic, and policy considerations. This work focuses on the tradeoff of input waste energy content to output electrical power, i.e. efficiency for waste-to-energy systems. Also presented is an approach for conversion technology selection based on characteristics of the waste stream, energy content of biogas generated from anaerobic waste treatment, and commercial applicability of five major prime movers across a large gradient of power output including: gas turbines, steam turbines, microturbines, reciprocating internal combustion engines, and solid oxide fuel cells. An efficiency model developed from fundamental thermodynamic principles is used to estimate the amount of power available from a waste treatment site, using data from a comprehensive data set of prime mover characteristics. A case study is presented, illustrating prime mover selection for three types of waste systems in Minnesota, United States: wastewater treatment plants, landfill sites and dairy farms. The results show that gas and steam turbines are recommended for large-scale systems with millions of gallons per day of wastewater generation, up to 60% of waste treatment sites. For small-scale systems applicable to distributed waste treatment and wastewater treatment facilities processing less than 10,000 gallons of water per day, fuel cells are recommended solely based on their high efficiency. Given the potential growth of decentralized waste-to-energy, the scarcity of highly efficient, affordable and fuel flexible power generation options necessitates further innovation in small-scale prime mover technologies.

Implications: Energy recovery from waste has not reached its potential due to several decision-influencing factors and technical challenges. Here an efficiency model is presented that theoretically validates efficiency curves for prime movers often shown in previous literature, but without physical verification. The developed regime model has significant practical utility as it concisely estimates power generation potential of a given waste treatment site. This work decouples decision factors by providing a practical template to better identify applicability of a prime mover to waste processing scenarios. In addition, the applicability analysis highlights areas in need of innovation, technology, and policy to address the changing landscape of waste treatment scale and potential opportunity to recover energy from small-scale distributed treatment facilities.

摘要

废物处理是未来全球能源组合的重要组成部分。在废物处理场所实施能源回收技术所面临的挑战包括相互交织的技术、经济和政策考虑。这项工作的重点是输入废物能源含量与输出电力的权衡，即废物能源系统的效率。还介绍了一种基于废物流特性、厌氧废物处理产生的沼气的能量含量以及五种主要原动机在大功率输出梯度上的商业适用性的转换技术选择方法，包括：燃气轮机、蒸汽轮机、微型涡轮机、往复式内燃机和固体氧化物燃料电池。根据基本热力学原理开发的效率模型用于估计废物处理场所的可用功率，使用来自原动机特性的综合数据集的数据。介绍了一个案例研究，说明了美国明尼苏达州三种废物系统的原动机选择：废水处理厂、垃圾填埋场和奶牛场。结果表明，燃气轮机和蒸汽轮机被推荐用于每天产生数百万加仑废水的大型系统，高达 60% 的废物处理场所。对于适用于每天处理少于 10,000 加仑水的分布式废物处理和废水处理设施的小型系统，推荐使用燃料电池，因为它们的效率很高。

含义：由于若干决策影响因素和技术挑战，从废物中回收能源尚未发挥其潜力。这里提出了一个效率模型，该模型在理论上验证了以前文献中经常显示的原动机的效率曲线，但没有进行物理验证。开发的制度模型具有重要的实际效用，因为它可以简明地估计给定废物处理场地的发电潜力。这项工作通过提供一个实用的模板来分离决策因素，以更好地识别原动机对废物处理场景的适用性。此外，适用性分析强调了需要创新、技术和政策的领域，以应对不断变化的废物处理规模格局以及从小型分布式处理设施中回收能源的潜在机会。